5 hard-boiled large eggs, chopped; 1 celery rib, finely chopped; 1/2 medium onion, finely chopped; 1-1/2 cups mayonnaise; 1/4 cup sweet pickle relish; 3 tablespoons sugar; 2 tablespoons dried parsley flakes; 2 teaspoons prepared mustard; 1 teaspoon salt; 1 teaspoon cider vinegar; 1/8 teaspoon pepper.